This application is based on application No. 8-336674 filed in Japan, the contents of which is hereby incorporated by reference.
The present invention relates to an image reading apparatus and method employing a linear CCD (Charge Coupled Device) sensor.
Conventionally, in the field of the image reading, there has been proposed a technique of improving the S/N (Signal-to-Noise) ratio of a read signal by summing outputs from a plurality of CCDs, as disclosed, for example, in the Japanese Patent Laid-Open Publication No. HEI 5-284283.
However, the aforementioned Japanese publication refers only to measures for improving the signal-to-noise ratio of the read signal and describes nothing about measures for increasing the operating speed.
A main object of the present invention is therefore to provide an image reading method capable of achieving a high-speed reading operation without increasing the operating speed of an analog processing circuit provided posterior to the CCD, and also to provide an image reading apparatus for carrying out such a method.
In an image reading method according to an aspect of the present invention, images in different positions of a document are simultaneously read by means of a plurality of line sensors to obtain respective image data while the document is being scanned. The respective image data are output in controlled sequence corresponding to the positions in which the images represented by the respective image data have been read. The images of the document are thereby reproduced.
This image reading method is implemented by an image read apparatus which includes:
a plurality of line sensors for simultaneously reading images in different positions of a document and outputting respective image data;
scanning means for making the plurality of line sensors scan the document; and
document reproduction means for receiving the image data from the plurality of line sensors and outputting the respective image data in controlled sequence corresponding to the positions in which the images represented by the respective image data have been read, to thereby reproduce the images of the document.
In an image reading method according to another aspect of the present invention, a first mode and a second mode are selectively set when performing image reading with a same resolution. The first mode is a high image quality mode which provides an image quality better than that in the second mode. The second mode is a high-speed reading mode which provides a reading speed higher than that in the first mode. Then, a document is scanned based on the reading mode selectively set, and images in different positions of a document are simultaneously read to obtain respective image data during the scanning.
This method is implemented by an image reading apparatus which includes:
a plurality of line sensors for simultaneously reading images in different positions of a document and outputting respective image data;
scanning means for making the plurality of line sensors scan the document;
reading mode setting means for, when performing image reading with a same resolution, selectively setting a first mode and a second mode, wherein the first mode is a high image quality mode which provides an image quality better than that in the second mode, and the second mode is a high-speed reading mode which provides a reading speed higher than that in the first mode; and
control means for controlling the scanning means based on the reading mode set by the reading mode setting means.
In an image reading method according to a further aspect of the present invention, an energy saving mode is set to read a document at a lower energy. Then, the document is scanned, and images in different positions of the document are simultaneously read to obtain respective image data during the scanning of the document. The thus obtained image data are subjected to a predetermined operation before being output for reproduction of the images of the document.
This method is carried out by an image reading apparatus which includes:
a plurality of line sensors for simultaneously reading images in different positions of a document and outputting respective image data;
scanning means for making the plurality of line sensors scan the document;
reading mode setting means for setting an energy saving mode to read the document at a lower energy; and
operation means for, when the energy saving mode has been set, performing a predetermined operation to the image data output from the plurality of line sensors.
The present invention further provides an image reading apparatus which includes image reading means, photographic mode setting means, discriminating means, reading mode setting means, and control means. The image reading means scan a document to output image data. The photographic mode setting means set a photographic mode in accordance with a type of the document. The discriminating means discriminate whether the photographic mode has been set or not. The reading mode setting means selectively set a normal image quality reading mode and a high image quality reading mode based on discrimination results. The normal image quality reading mode is set when the photographic mode has not been set, and the high image quality reading mode is set when the photographic mode has been set. The control means control the image reading means based on the reading mode set by the reading mode setting means.
Further, the present invention provides an image reading apparatus including a plurality of line sensors, scanning means, reading mode setting means, control means, and document reproduction means. The line sensors simultaneously read images in different positions of a document and outputting respective image data. The scanning means make the plurality of line sensors scan the document. The reading mode setting means set a high-speed reading mode. When the high-speed reading mode has been set, the control means control the scanning means to allow the plurality of line sensors to scan the document in a manner such that each of different parts of the document is read only once. The document reproduction means receive the image data from the plurality of line sensors and output the respective image data in controlled sequence corresponding to the positions in which the images represented by the respective image data have been read. Thereby, the images of the document are reproduced.
Other objects, features, and advantages of the present invention will be apparent from the accompanying drawings and from the detailed description that follows.